High temperature and pressure testing facility

ABSTRACT

A test facility is provided for testing materials under high temperature, pressure, and mechanical loads. The facility provides a physically scaled system that simulates conditions in hot sections of gas turbine engines. A test article is coated with a test material and exposed to a hot combusting flow in a test section housing. The article may be a pipe or conduit member oriented at any direction to the flow. A second cooler flow of fluid is channeled through the test article to create a sharp temperature gradient in the test article and through the test material. A liquid-cooled sleeve is disposed about the test article to create an annular channel of combusting flow over the test article. The downstream end of the second cooler flow is connected to the upstream end of the main hot flow at the combustion chamber.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is related to and claims priority to U.S.Provisional Patent Application Serial No. 60/418,549, filed Oct. 15,2002, entitled HIGH TEMPERATURE AND PRESSURE TESTING FACILITY, and U.S.Provisional Patent Application Serial No. 60/482,560, filed Jun. 25,2003, entitled HIGH TEMPERATURE AND PRESSURE TESTING FACILITY, theentirety of which is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] n/a

FIELD OF THE INVENTION

[0003] The present invention relates to a system and method for testingmaterials in high temperature and pressure environments, therebysimulating the conditions in a gas turbine engine.

BACKGROUND OF THE INVENTION

[0004] Testing of advanced components, materials, and coatings underextreme conditions that directly simulate engine operation is verycostly. In most cases it involves the installation of the testarticle(s) in a special test engine in the case of aircraft engines, orin an operating gas turbine in the case of industrial gas turbines.

[0005] Use of a special test engine is extremely expensive. The cost ofoperating a test aircraft engine can run as high as $10,000 peroperating hour. Since the test article must be tested for thousands ofhours to meet flight certification, full life engine testing must bereserved for final testing of hardware for qualification. Therefore alow-cost testing facility is needed that can test this hardware duringthe experimental, high risk phase of development, and where failure tothe test article does not have the potential to cause significant andcostly damage to the test facility.

[0006] For industrial gas turbines, an existing operating gas turbinemay be used. However, even this approach results in high costs due touncertainty of the test article's performance, life, and potential fordestructive failure, and the resulting impact on power plant's repairs,operability, and availability.

[0007] Existing testing facilities for testing hot section materialsystems are generally categorized as “burner rigs”. They typically usehot flame impingement onto the test article(s) to ascertainmaterial/coating durability under hot conditions. While these burnertests are more easily accomplished than full engine testing they excludesome of the effects that induce material and/or coating failures likethermal mechanical failure in the base metal, coating spallation due tohigh thermal gradients, erosion due to high velocity flow, corrosiondegradation due to trace elements in fuel at operating temperatures andpressures, ability to apply mechanical loads, and radiation loads in thecombustor. It is desirable therefore to provide a test facility thateffectively subjects test articles and materials to high heat andmechanical loads, high thermal gradients, high flow velocityenvironments, and other conditions exemplary of gas turbine engines.Furthermore, the test facility must be sufficiently scaled to meet costand operability requirements.

[0008] There are additional testing problems associated with testinghardware intended for advanced engines that are yet to be developed. Inthis case, existing engines cannot provide the operating temperaturesand pressures that this hardware will endure in the advanced engine.Again, a test facility that can provide these test conditions at lowcost would greatly increase design confidence while reducing the lifecycle cost for advanced engine development.

SUMMARY OF THE INVENTION

[0009] The present invention advantageously provides a test facility fortesting a material. The facility includes a test section housingdefining a first flow path and a second flow path, each flow path havingupstream and downstream ends, respectively. The facility furtherincludes a conduit enclosing a portion of the first flow path foraccommodation therethrough of a first fluid flow having a firsttemperature, and a sleeve concentric about the conduit to define anannular portion of the second flow path for accommodation therethroughof a second fluid flow having a temperature higher than the firsttemperature. A test material is disposed on the conduit in contact withthe annular portion.

[0010] In another embodiment of the present invention, a test facilityis provided for testing a material, having a test section housingdefining a primary flow path for accommodation therethrough of a firstfluid flow having a first temperature. At least one test articleencloses a portion of at least one secondary flow path for accommodationtherethrough of a fluid flow having a temperature lower than the firsttemperature. A test material is disposed on an outer surface of the atleast one test article in contact with the primary flow path.

[0011] In still another embodiment, the present invention provides a gasturbine engine simulation system. The system includes a test sectionhousing having a first flow pathway for the flow of hot combustingfluid, a supply means for providing compressed fluid to the testsection, and a combustion means for combusting the compressed fluid inthe first flow pathway. A test article is disposed in the test sectionhousing having a test material deposited on an outer surface of the testarticle, in contact with a portion of the first flow pathway. A firstcooling means is incorporated with the test article for providing atemperature gradient through the test article.

[0012] Yet another embodiment of the present invention provides a methodfor testing a material under high temperature and pressure. A compressedfluid is supplied to a test section having a first flow pathway. Aportion of the compressed fluid is directed through a second flowpathway defined in a test article disposed in the test section in aportion of the first flow pathway. Fuel is combusted with the compressedfluid to provide a high temperature and pressure fluid flow through theportion of the first flow pathway. A cooling fluid flow is providedthrough the second flow pathway to create a temperature gradient in thetest article.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

[0014]FIG. 1 is a schematic of the test facility system of the presentinvention;

[0015]FIG. 2 is a longitudinal cross-sectional view of a firstembodiment of the test section incorporated into the test facility ofthe present invention;

[0016]FIG. 3 is a perspective view of a section of the test pipe andcooling sleeve incorporated into the test section of FIG. 2;

[0017]FIG. 4 is a longitudinal cross-sectional view of a secondembodiment of the test section incorporated into the test facility ofthe present invention;

[0018]FIG. 5 is a perspective view of a longitudinal cross-section ofthe embodiment shown in FIG. 4; and

[0019]FIGS. 6A and 6B show alternate embodiments of a spring-loadedcompression seal incorporated into the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0020] As used herein, the term “high temperature and pressure” shallgenerally refer to those temperatures and pressures commonly found ingas turbine or other engine components, including, but not limited to,axial and centrifugal compressors, combustor sections, turbine sections,diffusers, nozzles, or any other component of turbomachinery or otherengines. Also as used herein, the term “test material” shall refer toone or a number of different substances, elements, compounds, ormixtures thereof, including a variety of thermal barrier coating (TBC)materials, or any other material in solid, semi-solid, or fluid form.

[0021] Also as used herein, a “facility” shall mean any device orarrangement of devices or systems, including individual components andaggregation of components. As used herein, a “conduit” shall mean anyobject having a path therethrough for the passage of a fluid. A path,which may also be referred to as a flow path or pathway, may be straightor curved, regular or irregular, and may include several independentpassages from one point to another.

[0022] Turning now to the drawing figures, FIG. 1 is a schematic of atest facility system arranged in accordance with the principles of thepresent invention. The test facility 100 includes a fuel source 101, andair source 102, a series of conduits 103 for carrying the compressed airfrom the air source 102 to a combustor section 104. A test section 105may be incorporated into the combustor section 104, where the twocomponents may form a single device. Alternatively, the combustorsection 104 may be separate and distinguishable from the test section,or may be detachable or removable therefrom. A heat exchanger such as anexhaust heat recovery unit 106 may be coupled downstream of the testsection. The heat recovery unit 106 may therefore be in thermalcommunication with the source of compressed fluid from the source 102.An exhaust valve and silencer unit 107 may be coupled downstream of theexhaust heat recovery unit 106, or directly downstream of the testsection 105. A load cell 108 may be incorporated into the test section105 to provide mechanical loads to a test specimen or article lodged inthe test section 105.

[0023] The air source 102 may also include several components, includinga motor 110, a gearbox 111, an inlet filter 112, and an industrialcompressor 115. Ambient air is drawn in through the filter 112 to thecompressor 115. The motor 110 and gearbox 111 drive the compressor 115,which outputs compressed air into the conduits 103 for delivery to thetest section 105. However, the present invention may use not only air asa fluid source, but any fluid, in gaseous or liquid form, as a source ofcompressed fluid which may be combusted and or mixed with fuel from thefuel source 101 in the combustor section 104.

[0024] As illustrated in FIG. 1, the present invention provides an opensystem that uses only enough working fluid flow to achieve sufficienthardware scale to lower testing costs. Controlled metric testing may beused to isolate critical empirical factors while testing across the fullrange of conditions to which hardware will be exposed in a real engine.The working fluid is provided by the source 102, where it is compressedby the compressor 115. The compressor 115 may use intercooling tocompress the air to a high pressure (such as 800 psia). Such a highpressure compressor may be either of the reciprocating or high speedcentrifugal design. The compressed air is then routed through conduits103 to the combustor section 104 and test section 105. The entire systemmay be arranged at a lower physical scale than that of a typical engine,but with enough of a flow to create an effective environment to testmaterials therein. By way of non-limiting example, exemplary flow ratesthrough test section 105 range from 0.25 lb/sec to 1.0 lb/sec.

[0025] The air exiting the compressor 115 may then be preheated in theexhaust recovery heat exchanger 106 (typically to a value of 1000° F. upto 1300° F.) prior to being sent into the combustor. However, such apreheating element is not necessary. Fuel such as natural gas or jetfuel is pumped to a pressure higher than that of the air to allow forproper distribution in the combustor 104 via fuel injection nozzles (notshown), where it is combusted to achieve very high combustor exittemperatures. A typical example of exit temperatures may be thestoichiometric limit for hydrocarbon fuels, which will result in atemperature of approximately 4000-4500° F.

[0026] Test articles or materials may be inserted into any portion ofthe flow in the test section 105, from the inlet to the exit. Or, thetest articles or materials, along with any instrumentation probes may beinserted into the combustion chamber 104. The test facility 100 isthereby able to apply both convection and thermal radiation loads on thetest article(s) inserted into the combustion chamber 104. Furthermore,the flame generated in the combustion chamber 104 may propagate into thetest section 105, such that thermal loads, including conduction,convection, and radiation loads, as well as erosive, fluid dynamic,mechanical, or other stresses and loads may be applied to the testarticle as desired.

[0027] After combustion, the flow is accelerated into the test section105 of the facility, which, in a first embodiment of the presentinvention, may include a cooled inner conduit or pipe within an outerpipe or sleeve. The inner pipe may have test material coupons orcoatings (not shown) deposited or fixed on its outer surface, which maybe loaded using the load cell 108 to evaluate both steady-state andtransient loads (such as vibration or pull loads). Realistic thermalgradients through the test samples are accomplished in the test section105 by simulating engine hot gas path conditions on one side of theinner pipe, and cooling side heat transfer on the other side. The testarticle may also be film cooled if desired. The load cell 108 controlsare located outside the test section 105 housing. For each of thecombustor 104, test section 105, and high temperature downstream parts,a combination of convective and film cooling is used to maintainmaterial operating temperatures within acceptable limits. As shown belowin FIGS. 2 and 3, the test section 105 housing includes a thermalbarrier coating lined metallic sleeve, possibly of copper, with channelsused as axial water jackets for advective cooling combined with latentheat via subcooled forced convection boiling.

[0028]FIG. 2 shows a detailed schematic of the test facility 100 withthe test article(s) in the test section 105 loaded such that they areparallel to the flow. FIG. 4 shows a similar schematic of the testfacility 100 where the test article(s) are loaded perpendicular to theflow. The test article(s) can be oriented at any angle to the flow. Upondiffusion out of the test section 105, the flow proceeds to the exhaustheat recovery unit 106 and is then cooled further, regulated down tonear ambient pressure and released to the environment through a silencer107.

[0029] In other embodiments of the present invention, the flow exitingthe test section 105 may first be expanded in a power turbine to reducethe discharge pressure and temperature into the heat recovery unit 106as well as to reduce the electrical power requirement of the facility100. This is especially true in the case of high speed centrifugal aircompressors which should prove more compatible than reciprocatingcompressors for accepting the high speed shaft power from such aturbine. For such configurations, it is also possible to yield a netpower production from the facility, or to create a power match betweenthe compressors and turbine such that no net power is required orproduced from the facility, aside from starting and shutdown.

[0030] The above-described facility 100 is started in the followingmanner. The industrial air compressor 115 is started via the electricdrive motor 110 and is brought to full test flowrate. In this condition,the compressor discharge pressure will be lower than testing pressuredue to the low temperature at the choked throttle (i.e. test section105). A fuel compressor is started via its drive motor and brought tofull test pressure and the fuel is injected into the combustor 104 andignited. At this point, the air compressor discharge pressure rapidlyachieves full test pressure.

[0031] Once the facility 100 is operating, control is maintained asfollows. The facility working fluid flow rate is controlled via thespeed of the air compressor 115. The temperature of the test section 105is controlled via fuel compressor speed and/or fuel control valves. Thetest section pressure then depends upon both the air compressor and theset test section temperature.

[0032] The facility 100 is shut down by first shutting down the fuelcompressors, thereby shutting off the combustion in the combustionsection 104. The air compressor 115 remains on until the facility 100 issufficiently cooled, and then it too is shut down. The safety featuresof this facility 100 may include containment of failed parts within thetest section as well as containment of the test facility 100 within thetest cell building, emergency fuel shutoff valves with atmosphericvents, and a fire extinguishing system for the facility.

[0033] The test facility 100 features operating costs far below those ofengine testing, while providing a test environment similar to that ofany existing or future gas turbine engine. Additionally, bothsteady-state and cyclic testing may be performed. The operating costsare a combination of fuel costs and electrical costs for operating thedrive motors. The electrical costs may be further reduced via powerpurchase agreements with local utilities that may include operationduring low-demand hours (such as at night) to provide low-costelectricity.

[0034]FIG. 2 is a longitudinal cross-sectional view of a firstembodiment of a test section 200 incorporated into the test facility 100of the present invention. FIG. 2 displays a test section housing 201which includes both a combustor section 202 and a central test section203. The combustor section 202 is therefore incorporated into theoverall test section 200, and is included in the same housing 201 whichincludes the main central test section 203. Alternatively, the combustorsection 202 may be separate from the central test section 203, and maynot be included in a single integrated housing, but may be separable orremovable from the central test section 203 housing. The test section201 is substantially axisymmetric about a central longitudinal axis 204,such that many chambers and passages defined therein are annular orbodies of revolution about the central axis 204.

[0035] The test section housing 201 defines multiple flow paths,including a first flow path 205, and a second flow path 210, each flowpath having upstream and downstream ends, respectively, which flowdirections are indicated by the arrows in FIG. 2. The first flow path205 generally corresponds to the non-reacting “cold” flow within thetest section 200, while the second flow path 210 generally correspondsto the combusting “hot” flow within the test section 200. Arrows 211,212, 213, 214, 215, 216, and 217 correspond to the cold flow within thefirst flow path 205. Arrows 221, 222, 223, 224, and 225 correspond tothe hot flow within the second flow path 210. The first flow path 205 isdefined by inlet channels or holes 231, which receive the compressed airfrom the compressor 115. The air at this stage is relatively cool whencompared with the flow elsewhere in the test section 200, but may stillexceed 1000 degrees F. in temperature. The compressed air flows throughinlet channels 231 along arrows 211 into an annular inlet chamber 232.The air is then directed in the direction of arrows 212 through radialorifices (not shown) on a central inner conduit 235, which is disposedin the test section housing 201 and centered substantially about thecentral axis 204 as shown. The cooler, compressed air then flows throughthe conduit 235 along arrows 213, 214, 215, and 216, in a leftwardsdirection as shown in FIG. 2.

[0036] The conduit 235 is coupled to radial conduits 238 which directthe air flow from the conduit 235 radially outwards to the inlet of theannular combustion chamber 240. The first flow path 205 effectively endsat the junction of the radial conduits 238 with the combustion chamber240, where incoming air is now mixed with fuel injected from one or morefuel injectors 242. The combustion chamber 240 effectively defines thebeginning, or upstream portion, of the second flow path 210 through thetest section housing 201. The combusting air and fuel mixture flowsthrough the annular combustor section 202 along arrows 221 and 222before entering an annular portion of the second flow path 210 betweenthe inner conduit 235 and an outer sleeve 250 concentric about theconduit 235. The hot combusting fluid flows along arrows 223 asindicated in FIG. 2 before exiting the sleeve 250 and entering anannular exit chamber 255 along arrows 224 as shown. The second flow path210 through the test section 200 thereby effectively terminates as theflow exits the exit chamber 255 through an exit conduit 260 along arrow225 as shown.

[0037] The portion of the second flow path 210 between the inner conduit235 and sleeve 250 is a region of very high temperature and pressure, aswell as considerable flow velocity. While temperatures may range as highas 4000 to 4500 degrees F., at pressures of up to 50 atm, the local flowMach number may be as high as 0.8: subsonic, but approaching thetransonic range. These conditions effectively simulate the conditions ina real engine, and allow for test materials to be subjected to severethermal, fluid dynamic, and mechanical stresses. A borescope 265 mayalso be provided to allow for observation of test materials deposited onthe outer surface of the inner conduit 235.

[0038] The present invention therefore provides a relatively low-cost,efficient means for testing a material under the severe loads of a realengine, without having to use a real engine or its components. Inparticular, the invention provides a steep temperature gradient throughthe wall of the inner conduit 235. The gradient is created between: (i)the flow of hot combusting gases through a portion of the second flowpath 210 between the inner conduit 235 and the outer sleeve 250, and(ii) the flow of relatively cool source air through the portion of thefirst flow path 205 inside the inner conduit pipe 235. The two flows maybe counter flows as shown in FIG. 2. Alternatively, the first flow path205 may be rearranged to be aligned in the same direction as the hotflow around the inner conduit 235. In either case, the resultantconvective cooling creates a sharp temperature gradient that provides asimulation of engine conditions previously unavailable in known testrigs. By way of non-limiting example, the temperature gradients achievedmay be in the range of between 250 and 1000 degrees F. across a testmaterial coating 0.020 inches thick. In addition, film cooling may belocally achieved over the surface inner conduit pipe 235 by providingholes or orifices therein.

[0039]FIG. 3 is a perspective view of a particular embodiment of asection of the inner conduit test pipe 235 and outer cooling sleeve 250incorporated into the test section 200 of FIG. 2. In this embodiment,the outer sleeve 250 includes a number of axial cooling channels 300which run parallel to the central axis 204 about which the conduit 235and sleeve 250 are centered. The cooling channels 300 are defined byradial sections created between an inner pipe 301 and an outer pipe 302of the sleeve 250, the sections being subdivided by a number of spars305 between the two pipes 301 and 302. Cooling channels can also bearranged to allow coolant to flow circumferentially around the housing.A coolant, such as water, or some other suitable coolant, is pumped intothe cooling sleeve 250 into the plurality of cooling channels 300 tocool the inner pipe 301, which is in contact with the hot combustingflow in the second flow path 210 through the test section. The coolerfluid first flow path 205 is also shown circumscribed by the section ofinner conduit 205.

[0040] Both the inner conduit 235 and the outer sleeve 250 may beaxially sectioned into interlocking attachable and detachable axialsections, such as sleeve sections 310 and 320 shown in FIG. 3. Eachaxial section may be fitted with complementary male and female threadportions on opposite axial sides of each section of the inner conduit235 and sleeve 250. The inner conduit 235 may therefore include aplurality of serially connected longitudinal pipe sections. The sleeve250 itself may have such interlocking threads on each of its inner andouter pipes 301 and 302, respectively. In this manner, the overalllength and dimensions of the test section apparatus can be scaled andadjusted to the needs of the user. Furthermore, differing test materialsmay be deposited or incorporated into different axial sections of theinner conduit 235, such that various test samples may be tested at thesame time. The test samples may also be inlaid into the conduit 235 inthe form of discrete surface sections or coupons, to allow for even morevaried test material arrangements.

[0041] Examples of flow conditions in the test section are as follows.Inside the inner conduit 235 in the first flow path 205, the flow may beat a pressure as high as 50 atm, a temperature as high as 1100 degreesF., and a Mach number as high as 0.6. Inside the portion of the secondflow path 210 between the inner conduit 235 and outer sleeve 250, theflow may be at a pressure as high as 50 atm, a temperature as high as4500 degrees F., and a Mach number as high as 0.8. The cooling waterflowing in channels 300 may be at significantly lower temperatures, suchas 100 degrees F. These channels are designed to handle the radialpressure differential developed by the difference in pressure dropbetween the incompressible coolant and the compressible hot gas as theyflow axially.

[0042]FIG. 4 is a longitudinal cross-sectional view of a secondembodiment of a test section 400 incorporated into a test facility ofthe present invention, such as the overall test facility described inFIG. 1. In this embodiment, test section 400 includes a housing 401,which includes both a combustor section 402 and a central test section403. As with the previous embodiment shown in FIG. 2, the combustorsection 402 is therefore incorporated into the overall test section 400,and is included in the same housing 401 which includes the main centraltest section 403. Alternatively, the combustor section 402 may beseparate from the central test section 403, and may not be included in asingle integrated housing, but may be separable or removable from thecentral test section 403. The test section housing 401 is substantiallyaxisymmetric about a central longitudinal axis 404; such that thechambers and passages defined therein may be annular bodies ofrevolution about the central axis 404.

[0043] The test section housing 401 defines multiple flow paths,including a first or primary flow path 405, and a second or secondaryflow path 410, each flow path having upstream and downstream ends,respectively, which flow directions are indicated by the arrows in FIG.4. The first flow path 405 generally corresponds to the combusting “hot”flow within the test section 400, while the second flow path 410generally corresponds to the non-reacting “cold” flow within the testsection 400. Arrows 411, 412, and 413 correspond to the hot flow withinthe first flow path 405. Arrows 421, 422, and 423 correspond to thecooler flow within the second flow path 410. Compressed air is suppliedthrough inlet holes (not shown) along arrows 411 into the combustorchamber 430 in the upstream portion of the first flow path 405 definedby the housing 401. The supplied air is mixed with fuel from one or morefuel nozzles or injectors 435. The hot combusting fuel and air mixturethen flows over a test article 440 disposed substantially perpendicularto the flow. The test article 440 could be disposed at any angle to theflow in the first flow path 405 by orienting the article 440 in thehousing 401 in the desired manner.

[0044] A second flow path 410 is defined first by an inlet chamber 450defined by the housing 401, into which compressed air is supplied alongarrow 421. This cooler air, having conditions comparable to the coolerair supplied into the first flow path 205 of the test section 200 shownin FIG. 2, enters an inner channel 460 defined within the test article440 and flows along arrow 422 as shown. The inner channel 460 terminateswithin the test article 440 at a longitudinal position downstream of theintersection of the test article 440 with the first flow path 405,whereby the air flowing within the test article 440 exits the articlethough holes (not shown) and flows along arrow 423 into an exit chamber465. This exit chamber 465 can function as part of a plenum, whereby theair flow can be routed to the input of the combustor section 402 andported into the combustor chamber 430. Another recirculation path may beprovided by linking the downstream chamber 468 of the primary flow path405 in the test section housing 401 with the inlet chamber 450 of thesecondary flow path 410 through a channel 469 as shown.

[0045] The flow of hot combusting fluid in the first flow path 405therefore flows around the test article 440 while cooler air flowswithin the article 440, to create a sharp temperature gradient throughthe walls of the test article 440, or through a test material that isdeposited onto the outer surface of the test article 400. Alternatively,the test article 440 may have a test material portion embedded therein,incorporated into a portion of its walls, or mechanically attached. Thearticle 440 may be of any shape or configuration, but is shown in FIG. 4to be shaped like a rod, with circular or elliptical cross-section. Thearticle 440 may also have an airfoil shaped cross-section. The article440 may be loaded with a load cell or other suitable loading mechanismto place a mechanical stress on the article 440, such as a tensile loadT as shown. The loads may be steady or transient, gradual oralternating, and may be used to mimic and simulate the conditions in areal engine. In this manner, the test section 400 may be used to subjecttest materials and test samples on the test article 440 to a variety ofcombined thermal, fluid dynamic and mechanical loads, so as to moreaccurately simulate the conditions in a real gas turbine engine.

[0046]FIG. 5 is a perspective view of a longitudinal cross-section ofthe test section 400 shown in FIG. 4. As shown in FIG. 5, the testsection 400 housing 401 includes several inlet holes or channels forincoming compressed air to be supplied into the combustion chamber 430.A plurality of test articles may be arranged parallel to one another asshown; to increase the available area of test samples and specimensexposed to the flow conditions inside the test section 400.

[0047] The test facilities described herein include several otherfeatures of note. The first is a removable front plate 275 included inthe embodiment shown in FIG. 2. The front plate 275 is disposed over aremoval channel or port 278 through which a proximal end portion of theinner conduit pipe 235 is disposed. The entire length of the innerconduit pipe 235 may be slidably disposed in the test section 200 andthrough the removal port 278, such that when the front plate 275 isremoved, the inner pipe 235 may be easily pulled out and repaired,refitted, or replaced as desired.

[0048] Another feature includes a seal and sealing mechanism present inboth the embodiments disclosed in FIGS. 2 and 4. FIGS. 6A and 6B showalternate embodiments of a spring loaded compression seal incorporatedinto the present invention. FIG. 6A is an enlarged view of the sealmechanism 280 in the test section 200 shown in FIG. 2. The seal 280seals the first flow path 205 between the inner conduit pipe 235 and thetest section housing 201. The seal 280 includes a spring 600 and twopiston rings 601 and 602, which are each circumscribed around the innerconduit pipe 235. Each piston ring 601 and 602 has an inner diameterthat is slightly smaller than the outer diameter of the inner conduitpipe 235 so as to provide a compression seal between the two elements.Furthermore, the load from spring 600 in the directions L as shownprovides a compression seal between the surface of the test sectionhousing 201 contacting each of the seals 601 and 602. Therefore, fluidflowing into the conduit 235 along arrows F as shown is sealed into thefirst flow path 205 and cannot escape the test section housing 201.

[0049] A similar arrangement of a seal mechanism 480 in the embodimentof FIG. 4 is shown in FIG. 6B. The seal 480 also includes a spring 610attached to piston rings 611 and 612, which each provide compressionseals between the test article 440 and the housing 401, to seal highpressure flow flowing through the portion of the secondary flow path 410along arrows F.

[0050] Both the test sections 201 and 401 in FIGS. 2 and 4,respectively, will require a fair degree of cooling, and may includeseveral cooling circuits or channels 700 about the various passages andchambers therein, as shown. Examples of materials used in constructingthe test section include various metals and/or alloys, includingstainless steel, or copper for the sleeve 250. Examples of testmaterials include various thermal barrier coatings, including anair-plasma spray coating. TBC coatings may themselves also be used toline the surfaces of the flow paths within the test sections 201 and 401to protect the sections.

[0051] It will be appreciated by persons skilled in the art that thepresent invention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

What is claimed is:
 1. A test facility for testing a material,comprising: a test section housing defining a first flow path and asecond flow path, each flow path having upstream and downstream ends,respectively; a conduit enclosing a portion of the first flow path foraccommodation therethrough of a first fluid flow having a firsttemperature; a sleeve concentric about the conduit to define an annularportion of the second flow path for accommodation therethrough of asecond fluid flow having a temperature higher than the firsttemperature; and a test material disposed on the conduit in contact withthe annular portion.
 2. The test facility of claim 1, furthercomprising: a combustor section defining a combustion chamber in fluidcommunication with the upstream end of the second flow path and thedownstream end of the first flow path, at least one fuel injectordisposed proximate the downstream end of the first flow path andproximate the upstream end second flow path.
 3. The test facility ofclaim 2, further comprising: a source of compressed fluid coupled to thetest section at the upstream end of the first flow path; and an exhaustchannel coupled to the downstream end of the second flow path.
 4. Thetest facility of claim 3, further comprising: a heat exchanger disposedin the exhaust channel in thermal communication with the source ofcompressed fluid.
 5. The test facility of claim 3, further comprising:an exhaust valve and silencer coupled to the exhaust channel.
 6. Thetest facility of claim 1, wherein the first fluid flow is oriented alongan axis in a first direction and the second fluid flow is oriented alongthe axis in a direction opposite the first direction.
 7. The testfacility of claim 1, wherein the sleeve defines a plurality of channelsfor accommodation therethrough of a fluid coolant.
 8. The test facilityof claim 1, wherein the conduit is a pipe having proximal and distal endportions, the pipe being slidably disposed in the test section housing,and wherein the test section housing further defines a removal portthrough which the proximal end portion of the pipe is disposed, and thetest section housing includes a removable plate covering the removalport, the pipe being removable from the test section housing through theremoval port.
 9. The test facility of claim 8, further comprising: atleast one seal sealing the first flow path between the pipe and the testsection housing, wherein the seal includes a spring and at least onepiston ring, wherein the at least one piston ring is disposed around thedistal end portion of the pipe to provide a compression seal between theat least one piston ring and the pipe, and wherein the at least onepiston ring is loaded by the spring to provide a compression sealbetween the at least one piston ring and the test section housing. 10.The test facility of claim 1, wherein the conduit comprises a firstplurality of serially connected longitudinal pipe sections.
 11. A testfacility for testing a material, comprising: a test section housingdefining a primary flow path for accommodation therethrough of a firstfluid flow having a first temperature; at least one test articleenclosing a portion of the at least one secondary flow path foraccommodation therethrough of a fluid flow having a temperature lowerthan the first temperature; a test material disposed on an outer surfaceof the at least one test article in contact with the primary flow path.12. The test facility of claim 11, further comprising: at least one fuelinjector disposed in the test section housing proximate an upstream endof the first flow path, wherein the test section housing defines acombustion chamber in fluid communication with the at least one fuelinjector, the combustion chamber occupying a portion of the upstream endof the first flow path.
 13. The test facility of claim 12, wherein thecombustion chamber is in fluid communication with a downstream end ofthe at least one secondary flow path.
 14. The test facility of claim 11,further comprising: a source of compressed fluid coupled to the testsection at the upstream end of the first flow path; and an exhaustchannel coupled to the downstream end of the first flow path.
 15. Thetest facility of claim 14, further comprising: a heat exchanger disposedin the exhaust channel in thermal communication with the source ofcompressed fluid.
 16. The test facility of claim 14, further comprising:an exhaust valve and silencer coupled to the exhaust channel.
 17. Thetest facility of claim 11, wherein the an upstream end of the at leastone secondary flow path is in fluid communication with the downstreamend of the first flow path.
 18. The test facility of claim 11, whereinthe first fluid flow flows over the at least one test article in adirection substantially perpendicular to a longitudinal axis of the atleast one test article.
 19. The test facility of claim 11, wherein theat least one test article comprises a plurality of test articles and theat least one secondary flow path comprises a plurality of secondary flowpaths.
 20. The test facility of claim 11, further comprising: at leastone seal sealing the at least one secondary flow path between the atleast one test article and the test section housing, wherein the sealincludes a spring and at least one piston ring, wherein the at least onepiston ring is disposed around a distal end portion of the at least onetest article to provide a compression seal between the at least onepiston ring and the at least one test article, and wherein the at leastone piston ring is loaded by the spring to provide a compression sealbetween the at least one piston ring and the test section housing. 21.The test facility of claim 11, further comprising: a load cell coupledto the at least one test article to mechanically load the test article.22. A gas turbine engine simulation system, comprising: a test sectionhousing having a first flow pathway for the flow of hot combustingfluid, a supply means for providing compressed fluid to the testsection, a combustion means for combusting the compressed fluid in thefirst flow pathway, a test article disposed in the test section housinghaving a test material deposited on an outer surface of the testarticle, in contact with a portion of the first flow pathway, and afirst cooling means incorporated with the test article for providing atemperature gradient through the test article.
 23. The gas turbineengine simulation system of claim 22, wherein the temperature gradientis at least 250 degrees Fahrenheit over a test material thickness of0.020 inches.
 24. The gas turbine engine simulation system of claim 22,further comprising: a load means for mechanically loading the testarticle.
 25. The gas turbine engine simulation system of claim 22,further comprising: a sleeve disposed concentrically about the testarticle to define an annular flow path therebetween, the annular flowpath coinciding with the portion of the first flow pathway, and a secondcooling means disposed in the sleeve for cooling the sleeve andproviding a heat sink for the hot combusting fluid in the first flowpathway.
 26. A method for testing a material under high temperature andpressure, comprising: supplying a compressed fluid to a test sectionhaving a first flow pathway; directing a portion of the compressed fluidthrough a second flow pathway defined in a test article disposed in thetest section in a portion of the first flow pathway; combusting a fuelwith the compressed fluid in the test section to provide a hightemperature and pressure fluid flow through the portion of the firstflow pathway; providing a cooling fluid flow through the second flowpathway to create a temperature gradient in the test article.
 27. Themethod of claim 26, further comprising: mechanically loading the testarticle.
 28. The method of claim 27, further comprising: depositing aplurality of test materials on the test article.